INDIANAPOLIS — A man on Indiana's death row for raping and fatally strangling an 18-year-old woman with her own shoelace must be given more time to prove he is too mentally ill to be executed, the Indiana Supreme Court said Wednesday.

Michael Dean Overstreet was convicted in 2000 of abducting, raping and killing Kelly Eckart of Boggstown in September 1997.

The state Supreme Court ordered the court that convicted Overstreet to review his claim, despite his previous appeals' rejection by state and federal courts. The justices said a U.S. Supreme Court decision makes it illegal to execute a person who is so severely mentally ill they do not understand the crime they committed.

Justice Robert Rucker wrote that a 20-page report by a forensic psychologist who examined Overstreet found that he lacked that understanding.

"Overstreet does not have, and does not have the ability to produce, a rational understanding of why the State of Indiana plans to execute him," Rucker wrote.

That, Rucker said, was adequate reason to allow Overstreet another appeal to the court that sentenced him. The court set a deadline of Sept. 13 for the petition to be submitted and ordered final judgment by March 3, 2014. The Supreme Court denied Overstreet's request that it hear his case.

No evidence of Overstreet's mental illness was presented during his four-week trial, though he had been diagnosed. The defense instead tried to prove that someone else killed Eckart.

Eckart was a Franklin College freshman, working her way through school with a part-time job at the local Wal-Mart. She was returning home from work when she was abducted from her car at a Franklin intersection.

Four days later, a hunter found her partially nude body dumped in a Brown County ravine near Camp Atterbury. She had been raped, shot in the forehead and strangled with her shoelace and a suspender strap.

DNA tests linked Overstreet to Eckart's body, and fibers found on her clothing also matched the carpet inside Overstreet's van, in which prosecutors said she had been transported.

Eckart's parents were not allowed to read a statement at Overstreet's trial. That led to passage of an Indiana law that guarantees that someone from a victim's family can make a statement to the court and the convicted murderer after a judge has announced the sentence.